With regard to these problems, the invention addresses the problem of providing an easily operated and compact device that enables a safe pressure relief of a corresponding hydraulic line.
According to the invention, this problem is basically solved by a device that has, in a control block to which the line to be relieved is connected, a relief valve in the form of an openable non-return valve. Via the non-return valve, a relief volume that reduces the line pressure can be fed into a pressure accumulator. The non-return valve can be opened by a manually moveable actuating member that is arranged so as to be moveable on the housing of the pressure accumulator. Before coupling a parked attachment to put it into service, any system pressure that may have built up in the attachment can then be easily and safely lowered to a pressure value at which the coupling process for connection to the working implement can be carried out easily and safely. The pressure relief according to the invention not only helps in relieving pressure due to a rise in temperature, but also in general because oil volume in the initially still closed system must be displaced during coupling. Furthermore, the force always acts in exactly the right moment (not too soon and not too late), namely when the counterforce is generated by the coupling. Due to the fact that the manually moveable actuating member for triggering the pressure relief is inventively arranged so as to be moveable on the housing of the pressure accumulator and that the pressure accumulator is a component of the actuating mechanism, the device can be particularly simple and compact in configuration and economically produced.
In a particularly advantageous manner, the housing of the accumulator and the control block can be combined into one structure, in which a direct connection of the fluid chamber of the pressure accumulator to the relief outlet of the non-return valve is formed. With such a construction, a minimum amount of installation space is necessary for the device. The entire device, including the pressure accumulator, can then be easily mounted directly on the attachment or inserted in a hose line running between the attachment and the working machine.
In particularly advantageous exemplary embodiments, provision is made of a pressure accumulator with a housing that extends along a longitudinal axis. The actuating member, in the form of an actuator rod, is guided coaxially through the housing to the closing body of the non-return valve. The closing body can be moved against a closing force into the open position by the actuator rod. Due to the fact that the actuating mechanism is integrated in the pressure accumulator in this fashion, the device can be configured with minimum overall dimensions. The control block is preferably designed such that actuating direction of the non-return valve always coincides with the actuating direction of the coupling, which allows easy manipulation, preferably one-handed operation.
In a particularly advantageous manner, provision is made of a pressure accumulator in the form of a spring accumulator, which has an axially moveable accumulator piston that is spring-tensioned, on its side facing away from the fluid chamber, by a compression spring and through which the coaxial actuator rod passes. The actuator rod extends by its inside end through the fluid inlet of the housing to the closing body of the non-return valve. The pressure accumulator can also be embodied as a spring accumulator in a cost-effective and compact manner. The relief system can also be embodied as a gas accumulator, which in certain circumstances leads to stringent requirements in terms of gas tightness.
For easy and convenient actuation, an actuator button for sliding the actuator rod manually can be mounted on the outside end of the actuator rod that projects above the external end of the housing of the accumulator.
For a particularly convenient manipulation of the device, the structure formed from the accumulator block and the accumulator housing can form a handle adjacent to the actuation axis formed by the housing. For carrying out a coupling process, the handle on the control block can be gripped with one hand and the actuator button can be simultaneously pressed with a finger of the same hand so that the operator's other hand is free to carry out the coupling process, for example by plugging in a plug-in coupling.
In particularly advantageous exemplary embodiments, the handle can form a connection part between a first coupling part having a line coupler and extending overhangingly along the actuation axis next to the accumulator housing. A second line coupler can be positioned on the actuation axis. The connection part extends in curved form between the coupling part and the second line coupler. Thus designed, the structure forms a comfortable and secure handle for the operator. Because the second line coupler lies on the actuation axis, the actuation direction for opening the non-return valve and the actuation direction for forming a plug-in connection to the second line coupler, for example, coincide so as to give rise to a favorable force direction for actuating the device.
In a preferred construction of the spring accumulator, the housing thereof is closed, on the end turned away from the fluid chamber, by a closing body against which the compression spring, in the form of a helical spring applying spring tension to the accumulator piston, abuts. The closing body has a tubular extension that extends axially inside the compression spring and in which the actuator rod passing through the closing part is guided so as to be axially moveable. With its extension, the housing end part thus forms the guideway for the actuator rod as well as an internal guide core for the helical spring surrounding the extension.
Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the drawings, discloses preferred embodiments of the present invention.